The invention relates to a data carrier including an electrical circuit, which circuit has receiving means adapted to supply input data, which input data may include an option control command, and which has option control command processing means to which the option control command can be applied and which are adapted to generate a port control command in dependence on the option control command, and which has port means to which the port control command can be applied and which can be set from one port state into another port state, which is complementary to said one port state, in dependence on the port control command, and which has at least one option means which is optionally accessible with the aid of the port means in dependence on the port states.
The invention further relates to a circuit for a data carrier, which circuit has receiving means adapted to supply input data, which input data may include an option control command, and which has option control command processing means to which the option control command can be applied and which are adapted to generate a port control command in dependence on the option control command, and which has port means to which the port control command can be applied and which can be set from one port state into another port state, which is complementary to said one port state, in dependence on the port control command, and which has at least one option means which is optionally accessible with the aid of the port means in dependence on the port states.
The invention further relates to a method of gaining access to option means with the aid of port means in a data carrier.
Such a data carrier of the type defined in the first paragraph, having a circuit of the type defined in the second paragraph and in which access to option means is enabled in accordance with the method of the type defined in the third paragraph, has been put onto the market by the Applicant as a so-called SIM card for a mobile phone.
In the known data carrier the port means are formed by a fuse stage, which is melted, i.e. brought into a non-conductive state, upon reception of a corresponding port control command, as a result of which access to optional memory means, provided as option means in the known data carrier and formed with the aid of an EEPROM, is inhibited irreversibly for the entire lifetime of the data carrier. The non-reversible state of the port considerably restricts the operating possibilities of the known data carrier.
It is an object of the invention to avoid the aforementioned restrictions of a data carrier of the type defined in the first paragraph and of a circuit of the type defined in the second paragraph and to provide an improved data carrier and an improved circuit.
The aforementioned object is achieved with a data carrier of the type defined in the first paragraph in that the option control command processing means are adapted to process at least one pair of mutually complementary option control commands and to generate at least one pair of mutually complementary port control commands, and the port means can be controlled reversibly as regards their port states in dependence on the two mutually complementary port control commands.
The aforementioned object is achieved with a circuit of the type defined in the second paragraph in that the option control command processing means are adapted to process at least one pair of mutually complementary option control commands and to generate at least one pair of mutually complementary port control commands, and the port means can be controlled reversibly as regards their port states in dependence on the two mutually complementary port control commands.
In order to achieve the aforementioned objects a method of the type defined in the third paragraph has the characteristic features in accordance with the invention, in such a manner that such a method can be characterized in the manner defined hereinafter, namely:
A method of enabling the access to at least one option means in a data carrier, which data carrier includes receiving means and option control command processing means and at least one option means, which method includes the steps defined hereinafter, namely requesting an option control command from an option control command supplier, and receiving the requested option control command, which when desired is received only upon payment of an option means enabling fee, and
transmitting the received option control command to the data carrier, in which data carrier the received option control command is processed with the aid of the option control command processing means so as to enable the access to the at least one option means.
As a result of the measures in accordance with the invention a data carrier and a circuit in accordance with the invention have the advantage that a reversible change-over of the port states of the port means is possible. Moreover, the advantage is obtained that access to the option means is enabled or disabled selectively in dependence on the currently active port state. Furthermore, the advantage is obtained that the operating possibilities of the data carrier are extended considerably and are far more flexible and that the operating possibilities can even be adapted to the prevailing operational requirements throughout the lifetime of the data carrier.
Furthermore, the advantage is obtained that the data carrier can be manufactured in very large quantities by a data carrier manufacturer. Another advantage is that a circuit manufacturer, i.e. a manufacturer of an integrated circuit which at least for the greater part forms the circuit of the data carrier, can manufacture the circuit of the data carrier at low cost. A further advantage is that after the data carrier or the circuit of the data carrier has been sold an option means can be enabled subsequently after the sale of the data carrier or the circuit of the data carrier at the request of a customer and upon payment of an option-means enabling fee, as a result of which the operating possibilities of a data carrier and a circuit in accordance with the invention are extended significantly when the owner of such a data carrier wants such an extension. This makes it possible to achieve a higher added value for such a data carrier.
With such a data carrier in accordance with the invention security requirements play a crucial role because the reversible control of the port states of the data carrier normally does not take place in a secure environment, where the security precautions are guaranteed by external security measures, but in a freely accessible and therefore unprotected environment and the risk of abuse is consequently very high. In order to allow for these stringent security requirements imposed on a data carrier in accordance with the invention and a circuit in accordance with the invention it has proved to be particularly advantageous when in addition the characteristic features as defined in claim 2 and claim 9, respectively, are provided. The provision of the characteristic features as defined in claim 2 and claim 9, respectively, has the advantage that the security precautions required in conjunction with the reversible control have been provided directly in the data carrier itself.
It has proved to be particularly advantageous when a data carrier in accordance with the invention and a circuit in accordance with the invention have the characteristic features as defined in claim 3 and in claim 10, respectively, because this makes it possible to enable or to inhibit access to a multitude of individual option means in a highly selective manner and because this makes it even possible to arrange option means in functional groups by enabling or inhibiting access to the respective group of options means via a single port means.
In a data carrier in accordance with the invention and in a circuit in accordance with the invention the option memory means can be formed with the aid of an EEPROM. However, it has proved to be advantageous to realize the option memory means with the aid of a flash memory because, as compared with an EEPROM, this flash memory requires a substantially smaller surface area on a chip which forms a part of the electrical circuit in accordance with the invention of the data carrier in accordance with the invention and the data carrier and the circuit as well as the chip can be manufactured particularly cheaply. Moreover, the advantage is obtained that an EEPROM included in the data carrier or in the circuit can be used chiefly for the storage of useful data, while applications are advantageously stored in the flash memory. Furthermore, a major advantage obtained in the implementation of an operating system for the data carrier in accordance with the invention and for the circuit in accordance with the invention is that only a basic part of the operating system has to be stored in a ROM, whereas an optional part of the operating system is advantageously stored in the flash memory, as a result of which an adaptation of the operating system to, for example, a modified standard can be performed in a highly flexible manner and without any problems by means of a software update of the optional part of the operating system, which part is stored in the flash memory.
As a result of the provision of the characteristic features as defined in claim 5 and in claim 12, respectively, it is advantageously achieved that the optional communication with the aid of the option bus means can be enabled only if necessary. This has the additional advantage that the stringent security requirements can be complied with to a maximal extent because an illegitimate communication with the aid of the option bus means is very unlikely to occur during an option bus means access which is enabled only when necessary, i.e. under well controlled conditions.
In the industry USB has developed into quasi-standard. Therefore, it has proved to be particularly advantageous to provide the characteristic features as defined in claim 6 and in claim 13 in a data carrier in accordance with the invention because this enables an optional communication with a multitude of apparatuses equipped with this quasi-standard to be realized under well controlled conditions.
By the provision of the characteristic features as defined in claim 7 and in claim 14, respectively, it is achieved in an advantageous manner that an increased need for computing power in a data carrier in accordance with the invention and in a circuit in accordance with the invention can be satisfied rapidly and flexibly with the aid of the option computing means, which can be activated optionally.
The aforementioned aspects as well as further aspects of the invention will be apparent from the example of an embodiment described hereinafter and will be elucidated with the aid of this example.
The invention will be described in more detail hereinafter with reference to an embodiment which is shown in the drawing by way of example but to which the invention is not limited.